Transposase enzymes are useful in in vitro transposition systems. They allow for massive-scale fragmentation and tagging of genomic DNA and are useful for making libraries of tagged DNA fragments from target DNA for use in nucleic acid analysis methods such as next-generation sequencing and amplification methods. There remains a need for modified transposases with improved properties and which generate tagged DNA fragments that are qualitatively and quantitatively representative of the target nucleic acids in the sample from which they are generated.